replPropertyMetaData sorting

[Stefan Metzmacher]

Hi Andrew,

> I've been looking, as part of my work at Catalyst, at issues around
> corruption of our DB due to replication issues.  Specifically, rename
> handling, particularly with subtrees. 
> 
> I found and fixed a number of bugs, which you will have seen in the
> braches I've proposed.  However, I've been less than satisfied with the
> tests for this area, so have been extending them.
> 
> I figured you might be very interested in the latest test findings,
> regarding replPropertyMetaData.
> 
> As far as I can tell, in windows 2012r2, the special sort order for
> replPropertyMetaData, that is with the RDN last, simply doesn't exist. 
>  Indeed, I wonder if it has always been an artifact of our DRS -> ldb
> conversion code in replicated_objects.c

Could be :-)
I'm also unable to see the rdn attribute metadata in any of LDAP searches
or ndrdumps of replication traces.

I guess the important thing is that we keep the rdn value uptodate/in sync
with the DN and the name attribute.

> I now have tests that query the server for the replPropertyMetaData and
> the DRS equivalent, after each operation, and it shows no such special
> sort order.
> 
> The only special thing I can find is that the RDN (eg CN) is given a
> local invocationID and a local version quite often, while remaining
> excluded from replication (name is replicated instead).
> 
> See http://git.catalyst.net.nz/gw?p=samba.git;a=shortlog;h=refs/heads/r
> epl_move-replPropertyMetaData
> 
> Thankfully because this is excluded over DRS, this has not caused
> replication corruption.
> 
> Finally, I do expect that the patches I have already written will cover
> the dbcheck flapping test, which was a genuine DB corruption, due to
> mishandling of renamed/deleted objects.

I don't have time for a deep review, but it looks
promising. Thanks a lot!

One comment regarding
https://git.samba.org/?p=abartlet/samba.git/.git;a=commitdiff;h=4f90f343fcbde0ace10e3b6cf65a78eba5b65762

From reading just the diff I'm wondering how this pass against Samba.

I had to add the following trick to get meta data stamps for empty
attributes in order to get
https://git.samba.org/?p=metze/samba/wip.git;a=commitdiff;h=340900584b39386cbb47655069bc15b93520a101
to pass see
https://git.samba.org/?p=metze/samba/wip.git;a=commitdiff;h=a95c629bd05f618cfcf7047a724b04231b842309
and
https://git.samba.org/?p=metze/samba/wip.git;a=commitdiff;h=c002e4724f8f36105b907d28381ec476a8f73ff9

This is part of the
https://git.samba.org/?p=metze/samba/wip.git;a=shortlog;h=refs/heads/master4-smart-ok
and
https://git.samba.org/?p=metze/samba/wip.git;a=shortlog;h=refs/heads/master4-smart-tmp
branches. I'll write more about that branches later....

metze

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